Developing an efficient garnet-type near-infrared phosphor Na 1.5 Gd 1.5 Sc 2 Ge 3 O 12 :Cr 3+ with relatively long-wavelength emission

Developing efficient near-infrared (NIR) phosphor with an emission peak wavelength over 850 nm is crucial to realize multi-functional spectroscopy applications, while this remains a significant challenge. Herein, a garnet-type Na 1.5 Gd 1.5 Sc 2 Ge 3 O 12 :Cr 3+ phosphor with an emission peak located at 882 nm was created from Na δ Gd δ Ca 3-2 δ Sc 2 Ge 3 O 12 :Cr 3+ (0 ≤ δ ≤ 1.5) solid solutions basing on the effect of cationic disorder. The maximum internal quantum efficiency (IQE) of Na 1.5 Gd 1.5 Sc 2- x Ge 3 O 12 : x Cr 3+ reached 84.6% when x = 0.01. The maximum external quantum efficiency (EQE) can be optimized to 20.6%. Using this material, a prototype NIR phosphor-converted light-emitting diodes (pc-LEDs) device was fabricated, which demonstrates an excellent prospect in spectroscopy applications.